Civil War Union Army Officer. After the Confederate bombardment of Fort Sumter, South Carolina, he recruited a company of infantry which became Company A, 7th Ohio Volunteer (Three-Month) Infantry, and was commissioned Captain on April 22, 1861. Promoted to Lieutenant Colonel on May 7, 1861, he served with the unit until its enlistment expired in June 1861. It was then reorganized as a three-year enlistment unit, and he remained as it’s Lieutenant Colonel. When the original Colonel of the regiment, Erastus B. Tyler, was promoted to Brigadier General, Willian Creighton was promoted to Colonel on May 20, 1862. He was severely wounded on August 9, 1862 at the Battle of Cedar Mountain, Virginia, leaving the regiment only to return to them in September 1862 after his second-in-command, Major Orrin J. Crane led the unit at the Battle of Antietam. Colonel Creighton led his men during the May 1863 Chancellorsville Campaign, and during the July 1863 Battle of Gettysburg, Pennsylvania, where the 7th Ohio Infantry fought on Culp’s Hill, and where a monument to the regiment stands today in the Gettysburg National Military Park. He traveled south to Georgia when the XII Corps was transferred to the Union’s Army of the Cumberland, and was placed in command of the 1st Brigade, 2nd Division in November 1863. On November 27, 1863, he was ordered to lead the brigade in an assault Taylor's Ridge near Ringgold, Georgia. The brigade struggled the entrenched Confederate defenders, and suffered severe casualties. Colonel Creighton, rallying his old regiment, was shot through the heart, carried down and died 6 hours later. He had previously tried to retrieve the body of Lieutenant Colonel Crane, who had been in command of the 7th Ohio Infantry, and who was shot near the top of the summit, but had been unsuccessful. Both Colonel Creighton's and Lieutenant Crane's remains were brought back to Cleveland, Ohio where they lay in state at City Hall on December 7 and 8, 1863. Both were temporarily placed in the Bradburn Family Vault in Erie Street Cemetery. Thousands of Clevelanders lined the street for the funeral procession. In July of 1864 both were buried, side by side, in Woodland Cemetery.